sms based stepper motor control

8/3/2019 Sms Based Stepper Motor Control

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SMS BASED

STEPPER MOTORCONTROL


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INTRODUCTION-:The project is aimed at developing and testing the use ofmobile phones to remotely control an appliance controlsystem. The microcontroller would then control a device based on the information given to it. The proposedsolution will need to be easy to use, simple, secure, androbust and be useful on most mobile phones. To achievethis testing will need to be carried out to create a usefulsystem.

The report consists of a background into the

area of 8051 microcontroller and mobile

communication, how they are interfaced to

each other and AT (Attention) commands set

used in communication.

HARDWARE USED

1.AT command supporting GSM mobilephone.

2.89S52 Microcontroller


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3.Max 232 IC.4.Relays5.Relay driver IC ULN 2803

6.Voltage regulator 7805.7.Diode IN40078.GSM Phone

SOFTWARE USED

1. Keil u-Vision 3.0

Keil Software is used provide you with software

development tools for 8051 based microcontrollers. With

the Keil tools, you can generate embedded applications

for virtually every 8051 derivative. The supported

microcontrollers are listed in the -vision

2 PRO51 Programmer Software

THEORY OF OPERATION


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In this project we interfaced 8051

microcontroller with Motorolas C168 GSM

mobile phone to decode the received

message and do the required action. The

protocol used for the communication between

the two is AT command.

The microcontroller pulls the SMS received by

phone, decode it, recognizes the

Mobile no. and then switches on the relays

attached to its port to control the appliances.

After successful operation, controller sends

back the acknowledgement to the users

mobile through SMS.

AT-Command set

The following section describes the AT-Command set. The commands can be tried

out by connecting a GSM modem to one of

the PCs COM ports. Type in the test-


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command, adding CR + LF (Carriage return +

Line feed = \r\n) before executing. Table gives

an overview of the implemented AT-

Commands in this application. The use of the

commands is described in the later sections.

AT-Command set overview

Command Description

AT

Check if serial

interface and GSM

modem is working.

ATE0 Turn echo off, lesstraffic on serial line.

AT+CNMI

Display of new

incoming SMS.

AT+CPMS

Selection of SMS

memory.

AT+CMGF

SMS string format,

how they are

compressed.


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AT+CMGR

Read new message

from a given memory

location.

AT+CMGS

Send message to a

given recipient.

AT+CMGD Delete message.

A BRIEF INTRODUCTION TO 8051

MICROCONTROLLER:

When we have to learn about a new

computer we have to familiarize about the

machine capability we are using, and we cando it by studying the internal hardware design

(devices architecture), and also to know about

the size, number and the size of the registers.

A microcontroller is a single chip that

contains the processor (the CPU), non-volatile

memory for the program (ROM or flash),

volatile memory for input and output (RAM), a

clock and an I/O control unit. Also called a

"computer on a chip," billions of


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microcontroller units (MCUs) are embedded

each year in a myriad of products from toys to

appliances to automobiles. For example, a

single vehicle can use 70 or more

microcontrollers. The following picture

describes a general block diagram of

microcontroller.

89s52: The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with

8K bytes of in-system programmable Flash

memory. The device is manufactured using

Atmels high-density nonvolatile memory

technology and is compatible with the

industry-standard 80C51 instruction set and

pinout. The on-chip Flash allows the program

memory to be reprogrammed in-system or by

a conventional nonvolatile memory pro-

grammer. By combining a versatile 8-bit CPU

with in-system programmable Flash on amonolithic chip, the Atmel AT89S52 is a

powerful microcontroller, which provides a

highly flexible and cost-effective solution to


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many, embedded control applications. The

AT89S52 provides the following standard

features: 8K bytes of Flash, 256 bytes of RAM,

32 I/O lines, Watchdog timer, two data

pointers, three 16-bit timer/counters, a six-

vector two-level interrupt architecture, a full

duplex serial port, on-chip oscillator, and clock

circuitry. In addition, the AT89S52 is designed

with static logic for operation down to zerofrequency and supports two software

selectable power saving modes. The Idle

Mode stops the CPU while allowing the RAM,

timer/counters, serial port, and interrupt

system to continue functioning. The Power-

down mode saves the RAM con-tents butfreezes the oscillator, disabling all other chip

functions until the next interrupt


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The hardware is driven by a set of program

instructions, or software. Once familiar with

hardware and software, the user can then


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apply the microcontroller to the problems

easily.

The pin diagram of the 8051 shows all of the

input/output pins unique to microcontrollers:

The following are some of the capabilities of

8051 microcontroller.


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Internal ROM and RAM

I/O ports with programmable pins

Timers and counters

Serial data communication

The 8051 architecture consists of these

specific features:

16 bit PC &data pointer (DPTR)

8 bit program status word (PSW)

8 bit stack pointer (SP)

Internal ROM 4k

Internal RAM of 128 bytes.

4 register banks, each containing 8registers

80 bits of general purpose datamemory

32 input/output pins arranged as four8 bit ports: P0-P3

Two 16 bit timer/counters: T0-T1

Two external and three internal

interrupt sources Oscillator andclock circuits.

THEORY-:


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Stepper motors operate differently from DC

brush motors, which rotate when voltage is

applied to their terminals. Stepper motors, on

the other hand, effectively have multiple

"toothed" electromagnets arranged around a

central gear-shaped piece of iron. The

electromagnets are energized by an external

control circuit, such as a microcontroller. To

make the motor shaft turn, first oneelectromagnet is given power, which makes

the gear's teeth magnetically attracted to the

electromagnet's teeth. When the gear's teeth

are thus aligned to the first electromagnet,

they are slightly offset from the next

electromagnet. So when the nextelectromagnet is turned on and the first is

turned off, the gear rotates slightly to align

with the next one, and from there the process

is repeated. Each of those slight rotations is

called a "step," with an integer number of

steps making a full rotation. In that way, the

motor can be turned by a precise angle.


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Stepper MotorAdvantages

and DisadvantagesAdvantages1. The rotation angle of the motor isproportional to the input pulse.


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2. The motor has full torque at standstill (ifthe windings are energized)3. Precise positioning and repeatability of

movement since good stepper motors havean accuracy of 3 5% of a step and this erroris non cumulative from one step to the next.4. Excellent response tostarting/stopping/reversing.5. Very reliable since there are no contactbrushes in the motor. Therefore the life of themotor is simply dependant on the life of thebearing.6. The motors response to digital input pulsesprovides open-loop control, making the motorsimpler and less costly to control.7. It is possible to achieve very low speed

synchronous rotation with a load that isdirectly coupled to the shaft.8. A wide range of rotational speeds can berealized as the speed is proportional to thefrequency of the input pulses.

Disadvantages1. Resonances can occur if not properlycontrolled.2. Not easy to operate at extremely highspeeds.

sms based stepper motor control

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